Method of cooking comestibles

ABSTRACT

A method and apparatus for &#34;deep-fat&#34; cooking of comestibles in which the comestibles are immersed in a bath of hot cooking medium maintained in a cooking vessel in which the heated medium is being continuously changed while cooking is taking place by flowing the heated medium into the bath and through and around the comestibles, overflowing it from the surface of the bath into a heating reservoir and reheating and recirculating it in a manner so as to sweep from the bath loose particles of comestibles so as to maintain the bath at the required cooking temperature. The overflow of the heated medium is filtered to remove the loose particles of comestibles before the medium is reheated and returned to the bath, and a small quantity of the oil is continuously drained from the cooking vessel during the cooking operation and completely drained from the vessel when the cooking operation is stopped so as to return the cooking medium to the heating reservoir.

1974 E. H. PALMASON 3,787,594

METHOD QT CUUKTNM MFQTTBPFR Filed July 30, 1968 4 Sheetr=-$heet 1INVENTOR 3O 8O EINAR H. PALMASON ATTORNEYS Jan- 7 E H PALMASON 3,787,594

METHOD OF COOKING COMESTIBLES Filed July 30, 1968 4 Sheets-Sher INVENTUREINAR H, PALMASON 1974 E, H. PALMASON 3,787,594

METHOD 0 COOKING COMESTTBLES Filed July 30. 1968 4 SheetsSheM x 35 7O IO:44 g 28 2 INVENTOR EINAR H. PALMASON 1974 E. H. PALMASON 3,787,594

METHOD OF COOKING LYFMESTTBLES Filed July (SO 1968 4 Sheets-Shem .1

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-92 INVENTOR Jag 1 EINAR H. PALMASON ATTORNEYS United States Patent US.Cl. 426-438 2 Claims ABSTRACT OF THE DISCLOSURE A method and apparatusfor deep-fat cooking of comestibles in which the comestibles areimmersed in a bath of a hot cooking medium maintained in a cookingvessel in which the heated medium is being continuously changed whilecooking is taking place by flowing the heated medium into the bath andthrough and around the comestibles, overflowing it from the surface ofthe bath into a heating reservoir and reheating and recirculating it ina manner so as to sweep from the bath loose particles of comestibles soas to maintain the bath at the required cooking temperature. Theoverflow of the heated medium is filtered to remove the loose particlesof comestibles before the medium is reheated and returned to the bath,and a small quantity of the oil is continuously drained from the cookingvessel during cooking operation and completely drained from the vesselwhen the cooking operation is stopped so as to return the cooking mediumto the heating reservoir.

This invention is in the field of art that covers the cooking ofcomestibles which is classified in the United States Patent Offioe inClass 99.

This invention relates to deep-fat cooking of comestibles and moreparticularly to an improved method and apparatus for preparing foodproducts in a heated bath of a cooking medium contained in a vessel inwhich the medium is continuously circulated during cooking byoverflowing a portion of it from the bath, the overflow filtered toremove loose, free particles of comestibles to prevent them fromremaining in the vessel and the filtered cooking medium heated andreturned to the vessel to maintain the bath at substantially constanttemperature and free of loose charred particles of comestibles.

Many methods have been proposed for the cooking of food products byimmersing them in a hot cooking medium. One such method is shown in thepatent to Martin, 3,210,193, in which hot cooking oil maintained at atemperature substantially higher than the desired cooking temperature isintermittently pumped into a cooking vessel while an equal amount of oilis removed from the bottom of the vessel, so that the temperature of theoil in the cooking vessel is always higher than the desired cookingtemperature. Another method is shown in the patent to Smith, No.2,767,095, in which the comestibles are cooked in a body of heatedliquid in an open atmosphere where the liquid dissolves substantialquantities of air. The liquid is continuously withdrawn from the system,heated, and the air removed from the liquid before returning the liquidto the system.

In the prior art methods, where an effort is made to improve the cookingrate by flushing hot oil over and around the articles being cooked, itis general practice to withdraw the oil from the cooking vessel which isat atmospheric pressure and force it through a heating vessel or astorage vessel which is always maintained full of oil or fat andtherefore under a pressure higher than that of the cooking vessel. As aresult, when fat or oil is absorbed by the food being cooked, the levelof fat or oil drops in the cooking vessel thus preventing any 3,787,594Patented Jan. 22, 1974 ice skimming or removal of loose particles fromthe surface of the hot fat or oil in the cooking compartment. Theseloose particles generally float on the surface of the hot fat or oil atleast until the contained moisture has been driven off and the particleis essentially charred when it then sinks to the bottom of the vessel.

If an attempt is made to filter this objectionable and probably harmfulmaterial from the cooking medium, it must be withdrawn from the bottomof the vessel and either sucked or pumped through a filter. The filteris therefore under the pressure of a head of the medium or pressure fromthe pump. Accumulation in the filter cannot be seen and it becomesditficult to clean the filter without interrupting the flow of thecooking medium and it is diflicult to determine when the filter needscleaning.

No attempt previously has been made to remove from the surface of a bathof hot cooking medium loose particles of comestibles before they havesubstantially charred so as to reduce the formation of harmfulbenzopyrenes, as well as to prevent foreign tastes and odors thataccumulate in cooking oil and fat causing darkening and damage,particularly where more than one type of food product is cooked in it,and where the food being cooked is drenched in corn meal or batter orcrumbs.

I have found that an excellent food product is produced by the rapidcooking as set forth in my invention, which food product has relativelylow fat or oil absorption and a high degree of crispness. This isachieved by cooking in a vessel or isolated portion of a vessel having abath of heated cooking medium, such as cooking oil or fat, that iscontinuously circulated through the food as it is cooked in a manner sothat the loose particles of the food present in the cooking medium areswept out of the bath by continuous overflow of the cooking medium fromthe bath. The overflow of cooking medium is filtered to remove the loosefood particles entrained therein before it is heated and returned to thecooking vessel. Also the condition of the filter may be easily seen andthus may be cleaned, automatically or manually, without interrupting theoperation of the cooker Whenever large amounts of loose particles ofcomestibles have been collected in it. The filter, when exposed, may belifted out and cleaned or replaced anytime it is found to be full ofparticles. In the case when the filter has a raised cover over it, whenthe filter is filled it retards the flow of oil so that the level of oilin the cooking vessels will begin to rise. This automatically drops thelevel of oil in a reservoir which causes a float switch to disconnect apump motor and flashes a signal light to change filter.

This invention presents an advance in the art of cooking by deep-fat"immersion of comestibles retained in a suitable fiow-through cookingbasket positioned in a cooking vessel having in it a hot cooking medium.The cooking medium is continuously pumped into the bath, circulatedthrough the food in the cooking basket, and overfiowed from the cookingvessel and into a screen or filter, all during the cooking cycle of thecomestibles. As the cooking medium passes through the basket, it picksup or sweeps particles of the food or crumbs which break loose or fallaway from the comestible, carrying them out of the cooking basket intothe oil bath. The rate of oil flow and the shape of the cooking vesselcause these loose particles to be swept from the vessel into a filter orscreen, thus cleaning the exiting oil and preventing the particles frombecoming charred by remaining in the hot oil. It will be appreciatedthat the overflowing cooking medium is then at its lowest temperature,having given up heat to the food being cooked, and is then cleaned andreheated.

Thus there is provided an effective clearing of the cooking medium bythe overflow of particles of comestible that adversely affects the tasteof the cooked product if they are allowed to remain in the cookingmedium and become charred.

In the method of cooking by my invention, the food particles detachedfrom the comestible being cooked, such as crumbs from breaded articlesor small pieces of food, do not remain in the cooking bath where theycan be charred by overcooking which can produce in the bath theundesirable chemicals that may be harmful if consumed. The cookingmedium is thereby maintained in a fresher condition free of odors andappreciably unaffected in taste qualities. Also, because of the rapidflow of cooking medium into the cooking vessel or chamber, a heatinsulating layer of cooled cooking medium does not build up on the foodbeing cooked. Food is therefore more rapidly cooked and absorbs andcarries with it less cooking medium so it has a lower fat or oil contentwhen taken from the cooking bath which provides for a tastier cookedfood product having a lower caloric value, and having increased appealto the consumer. In addition, steam present in the medium is removedwith the overflow so it can pass off to the atmosphere and is notabsorbed into nor does it cling to the food product where it canrecondense as water and destroy the crispness of the cooked food.

This invention utilizes a cooking tray or table that has one or moredeep well cooking vessels or receptacles in it, filled with a moving hotcooking oil with a surface overflow means and a means for introducingheated cooking medium to produce a flow directed so as to clean thecooking vessel and cause a continuous changing of the cooking medium inthe vessel during cooking. The surface overflow means and the means forintroducing the hot cooking medium are spaced apart so that the mediumbeing introduced into a vessel is swept through and around comestiblesimmersed in it thus cooking them and conveying off these loose particlesby way of the overflow to prevent their charring and remaining in thevessel. This flow of the hot cooking medium over the overflow means isthen passed through a filtering or screening means where the particlesare removed, the cooking medium then flowing by gravity to a heatingarea and to a pump that returns it heated to the vessels. The food thuscooked by the method of this invention is substantially free of odor andin particular the equipment is capable of cooking many types of foods inthe same medium without one having the taste of the other. For example,fish and potatoes can be cooked in the same medium with each maintainingits individual taste without any taste contamination from the other.

Advantageously, the method of cooking comestibles of this invention canbe carried out in a portable cooking unit in which a plurality of deepwell cooking vessels or receptacles may be used, with each vessel havinga weir or spillway connected to it over which hot cooking medium such asoil or fat overflows. In such a system, the hot oil is introduced at thedesired cooking temperature through a distributor means in the vesselwith the oil being directed downwardly and outwardly into the interiorof the vessels so as to sweep through comestibles immersed in it causingturbulence to lift loose food particles to the surface and then overflowthem from the vessels. The overflowing oil carries the loose particlesof comestibles that have broken away from those in the cooking basketsand these particles are left in the screen or filter before the filteredoil is passed to a reservoir where it is heated and then returned bypumping to the distributors positioned in the vessels.

Thus, by providing a circulating system in which a supply of cooking oilis pumped from a reservoir containing oil under atmospheric pressure,through oil heaters to maintain the oil at the desired cookingtemperature and then into oil distributors for sweeping the oil throughcomestibles immersed in it with a quantity of oil being introduced thatwill provide a constant overflow, there is provided a deep-fat fryingsystem that will effect the frying of foods crisply and evenlythroughout while maintaining fresh taste and aroma and be devoid of thetaste of other foods that may be cooked in the oil.

Advantageously, the cooking oil reservoir in the form of a supply tankcan be arranged so that the filtered oil flowing from the overflow meansenters it above the maintained level in the tank thus providing forrelease of steam or entrained air that may affect the oil circulation. Avent means may be provided to release this air or steam so that there islittle or no accumulation in the reservoir and assure continuousfunctioning of the apparatus without steam or air locks.

It will be appreciated that venting the oil reservoir maintains it atatmospheric pressure similar to the pressure maintained in the cookingvessel. The oil in the reservoir is also maintained at substantially theselected cooking temperature by the heaters in the tank. Because the oilflowing through and around the piece of comestible prevents an envelopeof cool, insulating oil from coating the cold comestible when it isfirst immersed in the hot bath, the cooking time is thus shortened ascompared to normal deep-fat fryers which use convection to circulate thecooking oil; therefore, the temperature of the oil in the system of myinvention can be kept lower than the cooking oil temperature used inconvection type deep-fat" frying units.

Another apparatus and method of operating by this invention isparticularly advantageous when only a small or intermittent output isrequired from the deep-fat fryer. Here, the oil overflow from thecooking vessel flows by gravity into the reservoir Where it ismaintained at cooking temperature. The bottom of the cooking vessel hasa small drain means that bleeds oil a constant stream of the oil througha small filter screen and passes it to the reservoir. When the cookingoperation is stopped, the oil in the vessel passes into the reservoirwhere it is heated and retained ready for use. Also where fat is used asthe cooking medium that solidifies under cooling temperature conditions,the draining of the hot fat from the vessels into the reservoir as soonas the pump has been shut off prevents it from solidifying in thecooking vessel.

It will be appreciated that in the cooking system of my invention when aswitch is activated, usually by means of lifting a cooking basket from ahanger bracket support, the pump starts and immediately brings hotcooking medium into the cooking vessels where it goes around and throughthe comestible and overflows a lower side in the cooking vessels, thenthrough a screen or filter, and back into a reservoir which may also bea heating section. The system and apparatus of this invention has theadvantage of keeping cooking oil or fat all in one reservoir, heldsubstantially at the cooking temperature, and it limits the amount ofexposure of hot oil or fat to the air as is necessary during theoverflow filtration to prevent oxidation of the oil or fat. Also it hasbeen found that by the use of a positive displacement oil delivery pump,heated oil is effectively and continuously delivered during the cookingoperation and particularly for that type of cooking operation wherequick starting and stopping is desired.

Additional objects and advantages of the invention will be more fullyappreciated by reference to the accompanying drawings and a descriptionof them which are illustrative of a preferred embodiment of theinventive concepts herein, in which:

FIG. 1 is a view in perspective of a portable deepfat" frying unitembodying my invention showing two cooking vessels separated by anoverflow means for producing an overflowing of hot cooking oil when theoil is circulated during cooking;

FIG. 2 is a top plan view of the unit shown in FIG. 1 showing therelationship of the hot oil distributors positioned in the vessels forcirculating the oil and the overflow device for the removal of the oilfrom the cooking vessels;

FIG. 3 is a front view in elevation of the frying unit of FIG. 1 with aportion of it broken away to show the relationship of the cookingvessels, the overflow device and filter, the reservoir and the pump thatcirculates the heated oil through the unit;

FIG. 4 is a side view in elevation of the frying unit of FIG. 1 with aportion of it broken away to show the tray for holding the cookingvessels, the cooking vessels in relation to the overflow device and thedistributors for the circulating of heated cooking oil;

FIG. 5 is a schematic representation of the unit shown in FIGS. 1, 3 and4 illustrating the ingress of hot cooking oil through distributors intothe cooking vessels, the typical flow of the oil in and through thevessels, the overflowing of the oil through a filtering device to thereservoir, and the pump means for returning the oil to the distributorsafter it has been heated; and

FIG. 6 is a wiring diagram showing the control system for starting andstopping the operation of the apparatus.

In the drawings, numeral 10 represents the deep-fat" frying unit ordevice of this invention for cooking comestibles by immersion in a hotcooking medium such as oil or fat. The device has a cooking tray 12 madepreferably of stainless steel that provides a cooking work area. Locatedbelow the work area is a cooking oil storage, heating and circulatingsystem 14 which provides a reserve of hot oil which it maintains at asubstantially constant cooking temperature and circulates to the cookingvessels when comestibles immersed in the cooking oil are being cooked.Supporting the cooking tray 12 is a structural frame 16 having asupporting base 18 to which casters 20 are attached to make the unitportable in those cases where portability of the deep-fat frying unit ofthis invention is desired. The structural frame has upright framingmembers 22 and cross framing members 24 for support of the cooking trayunit and the associated storage, heating and circulating system. Front,rear, and side panels 26 are attached to the framing members to enclosethe deep-fat frying device.

The cooking tray 12 is an integrally formed structure having a beadedouter edge 28 that surrounds the periphery of the cooking tray andencloses a sloping o-il drainage shelf 30, and a pair of spaced cookingvessels or receptacles 32 which are separated by a cooking oil overflowdevice 34. In line with the cooking vessels and on the back uppersurface of the cooking tray are a pair of hanger bracket supports 35 forrespectively supporting one of a pair of deep-fat cooking or fryingbaskets 36 out of the oil so that they can rest above or drain into thevessels when cooking is not taking place. The baskets have a roundedbottom configuration and are adapted to fit into one of the cookingreceptacles for immersion cooking of the comestibles placed in thebaskets. The baskets are of a height so that when resting on the bottomof the vessels during cooking the upper rim of a basket is above thecooking oil level in the vessel. The baskets also have a handle 38 bywhich they are easily manipulated (See FIGS. 2 and 5).

The cooking vessels 32 are elongated troughs each having asemi-cylindrical bottom portion 40, rear end wall 42, and a front endwall 44. The semi-cylindrical bottom portion at the outboard sideextends upwardly to the beaded outer edge 28 while the inboard sideextends upwardly to join the overflow device 34. The rear end wall 42extends upwardly from the bottom of each vessel to the beaded outer edge28, and the front wall 44 of each vessel extends upwardly to thedrainage shelf 30. (See FIGS. 3 and 4.)

The rear end wall 42 of each vessel has an aperture or opening throughwhich a tube or conduit forming the oil distributor is passed, and means(not shown) are provided to seal the end wall around the distributor toprevent leakage. Also, it will be seen that the extension of the bottomportion of the vessels is higher outboard than inboard so that theoverflow device 34 is lower than drainage shelf 30, which is inclined inorder to provide for drainage of hot cooking oil which may drip onto theshelf as the comestibles are being prepared for use, and provides for aweir flow for the overflowing of the cooking oil from the vessels duringcooking. The bottom portions of the cooking vessels each also defines anoil drain hole 46 for bleeding off a small quantity of oil from near thebottom of the oil forming the bath in the vessels during and aftercooking and the drain hole has a drain screen 48 positioned in it toprevent clogging.

The oil overflow device 34 is positioned longitudinally between thecooking vessels, extending between them to connect at one end with therear end walls 42 and at the other end with front end walls 44. The oiloverflow device is of V shaped cross-section and positioned between thecooking vessels or receptacles so that the tops of the V form a weir oroverflow means 50 with each vessel for cooking oil spillover. The Vformed by the two weirs provides a trough-like housing 52 closed atfront and rear by housing ends 53 and 54 and which provides a housingadapted to retain a removable filter 56 for filtering the oil spillinginto the overflow device. The top portion of the housing defines anopening 58 which is supported in such a way as to allow the oiloverflowing the weirs to substantially fill the housing and pass throughthe filter to filter out and retain particles of comestible from thecooking oil.

Positioned near the level of the oil in housing 52 in one of the housingends and behind the filter is an oil return aperture 59 that isconnected to oil return conduit 60 which extends into an oil reservoiror tank 62 for passage of filtered oil from the overflow device to thereservoir when the cooking operation is in progress. The oil levelduring cooking is designated by dash line A in FIG. 3. The reservoir 62is positioned below the bottom of the housing so that oil passingthrough the filter returns by gravity flow to the reservoir. A small oilbleed aperture 63 is also defined in the bottom of the housing and isconnected with the reservoir by bleed line 64. This arrangement providesa drain or bleed-off flow of oil from the lower portion of the housinginto the reservoir during cooking and to empty oil out of the housingafter cooking is completed.

The drainage of cooking oil from the bottom of vessels 32 through drainhole 46 and screen 48 is also passed to reservoir 62 through drain lines65. These lines are of a size so as to permit a continuous controlledamount of drainage of oil from the vessels into the reservoir during thecooking operation, and the screens 48 keep loose pieces of comestiblesthat may be on the bottom of the vessels from exiting through thesedrain holes. When the cooking operation is stopped, the oil drainscompletely from the cooking vessels and is deposited by gravity in theheated reservoir and the oil level then is at B as is illustrated bydash line in FIG. 3.

The return conduit 60 extends into the reservoir and its exit end ispositioned below the oil level A and above a pair of oil heaters 66 and68 located in the reservoir. Positioned below the exit end of conduit 60above the heaters is a dished bafl'le deflector 69 which intercepts theentering flow of oil moving downward from the conduit into the oilsupply in the reservoir and provides for deflecting this flow upwardfrom just below the level of the oil supply and directing it towards thesurface of the oil so that gases entrained in the oil can separate outand water pass off as vapor or steam and be released from the surface ofthe oil. A vent 70 is provided on the reservoir for venting any air orsteam from it so as to prevent cavitation and loss of pump suctionduring circulation of the oil in the system.

The oil reservoir 62 has an enlarged upper cross-section that providesspace for holding the cooking oil when the unit is not in operation andfor a change of its level when the circulation of the oil takes placeduring cooking. Below the enlarged upper cross-section is a smallercross-section which provides a well or sump in which electrical heaters66 and 68 are positioned. It is appreciated that other types of heatersmay be used and that the heating of the reservoir can be accomplished bya jacketed heating means surrounding it. In order to provide efiicientheating of the oil in the sump, two baffles 71 and 72 are arranged so asto allow for distributing of the oil normal to its flow direction, thusproviding more efficient heating of it. The lower section of thereservoir near the bottom thereof has an outlet opening 74 whichprovides for the passage of oil from the reservoir during cooking.

An oil pump 76, which preferably may be a positive displacement typepump, is energized by motor 78 and is operatively connected at itsintake end to reservoir 62 and at its discharge end to conduits thatfeed oil distributors 80. The intake end of the pump is connected tooutlet opening 74 by conduit 82 and the discharge side of the pump isconnected to conduit 84, which in turn is connected to header conduit86, which is connected to distributor feed pics 88. The feed pipes 88are connected to vessels a turbulent, continuous flowing of oil aroundand through the comestibles being cooked, where it then overflows and isfiltered and returned to the reservoir for recycling to the cookingvessels (see FIGS. 3, 4 and The reservoir has a draining valve 89 in thebottom of it for replacing the cooking oil when the oil needs to be 1changed. Also, the cooking oil overflow device 34 is provided with acover 90 that covers the opening in the overflow device and preventsfood or other particles from falling into the device. The cover alsoaids in the control of the flow of the cooking oil over the weir byhaving the oil flow under the bottom edge of it, thus helping to providea smooth overflow.

Exemplary of a suitable portable unit for deep-fat cooking usingstandard open mesh cooking baskets is a unit having one or more deeprounded bottom cooking vessels. It has been found that very good resultscan be obtained when the cooking vessels have a length from about inchesto about inches, a width of about 6 inches to about 10 inches and adepth of about 4 inches to about 8 inches, it being appreciated thatlarger vessels can also be used. The cooking medium in the unit can bemaintained at a temperature of from about 300 to about 390 F., with acirculation rate of from 2 to 20 gallons a minute and a cooking mediumcapacity of 2 to 10 gallons in the total system. A portable unit of thetype set forth above cooked such items as potatoes, clams, chicken,fish, meat, shrimp and other fryable food in a minimum of cooking timewith the elimination of scorching and the accumulation of charred foodparticles in the vessel so that the resultant cooked product was freefrom odors. This occurred even when difierent fryable foods were cookedin the same medium.

An instrument or control panel 100 is provided at the front of thedeep-fat frying unit 10 for housing control switches and operatinglights used in the operation of the frying unit. Controls for the pump,heaters and other parts of the electrical system include switch 104,which energizes the electrical system, and a pump motor relay switch 106that energizes the motor 78 through its relay 107. Switch 104 energizessignal light 108 which signals an on or oil condition of the unit.Switches 104 and 106 are connected across a source (not shown) of 117volt AC. power, with the motor switch providing hand control operationof the oil pump motor 78. Also operatively connected across the 117 voltA.C. power source is a manually controlled oil heater switch 110 forplacing the heater in condition of being electrically energized. Theheater and its switch is connected to a heater pilot light 112 to signalwhen the heaters are in operation. Heater elements 92 are controlled bya heater relay 114 housed in a contactor box 116, the relay connected sothat the heaters are in parallel across a source (not shown) of 240 voltthree-phase AC. power. A heater terminal box 118 is provided forconnecting the heaters with the heater relay.

An oil temperature control thermostat 120 can be set by a calibratedknob or other suitable mechanism (not shown) so as to set the output ofthe heaters to maintain the cooking oil at the desired temperature. Atemperature control and sensing probe 122 is positioned in the returnflow of oil from the overflow means and controls thermostat 120 tomaintain the desired cooking temperature of the oil in the reservoir.The thermostat 120, in association with pilot light 112 which signalswhen the heaters are in operation, are connected across the 117 voltA.C. power source controlling energy to heater elements 92 in theheaters 66 and 68, through thermal relay 114.

An overheat thermostat 124 has a temperature sensing probe (not shown)attached to the outer surface of the reservoir which controls theoperation of it. The overheat thermostat 124 provides a lock-out of theelectrical system when oil in the reservoir is heated above the desiredset cooking temperature. When this occurs, a signal light 128 shows thatthe heater operation is locked-out, thus protecting the cooking oil fromoverheat damage.

A low oil level safety device 130' is located in the oil reservoir 62and has a cut-out switch 132. The safety device 130 provides a cut-outmeans which disconnects the power to the pump motor shutting down thecirculation of oil in the unit and deenergizing the heaters when thelevel of cooking oil in the reservoir falls below level A. The safetydevice 130 is operated by a float 134 which floats on the surface of theoil in the reservoir and is attached to the end of a lever 134 thatextends through a seal in an opening through the side of the switchhousing 138 and is fulcrumed to operate the safety switch 132.

An open condition of the switch 132 disconnects power to the electricalsystem except that it energizes signal light 140 that indicates that oilshould be added. A preheat thermostat 142 is provided for holding thepump out of operation until the oil has been heated to the desiredcooking temperature.

When the unit is not in use, or after the cooking operation has beencompleted, each basket is placed on its hanger bracket support 35 andmaintains a pump hold out switch 144, connected into the controls forthe unit, in position so that no energy is produced for the pump motor.There is a time-delay mechanism operatively associated with the switches144 so that, when the baskets are in place on the brackets, the pump ispermitted to operate only for a short period of time to insure that theoil in the vessels is cleaned by passage through the filter.

In operation, the deep-fat" fry unit of this invention is first suppliedwith a cooking means, such as oil or fat. The oil or fat necessary tofill reservoir 62 to level B as shown in FIG. 3 provides sufficient oilfor the operation of the unit. The oil can be put in the reservoir 62 byremoving cover and then pouring it into the overflow device 34 where itpasses into the reservoir until level B is reached. Level B is reachedby pouring in the amount of oil that is designated as the capacity forthe unit. With the oil in the unit at level B, one of the frying basketsis removed from its bracket support 35, allowing the holdout switch 144to close so that the system may be energized. Then the main switch 104is turned on, energizing the system, and the oil heater switch is turnedon and the heaters 66 and 68 are energized. At this point, the heaterpilot light 112 is energized, showing that the cooking oil is beingheated. When the oil is at the proper temperature to insure that it isfluid and pumpable, the thermostat 142 energizes the relays 114 and 107,allowing the pump to start circulating the oil. The oil continues toheat until the oil temperature control thermostat registers thepre-selected cooking temperature at which point it de-energizes,allowing energy to flow to the relay 114, thereby dropping the heatersout while the pump continues to circulate. The cooking basket may thenbe replaced on its bracket support which shuts off the pump after atime-delay. The deep-fat frying unit is then ready for cooking operationand, with cooking baskets 36 positioned on hanger bracket supports 35,the pump relay motor switch 106 having been placed in the on position byhand the pump is prevented from operating by pump hold-out switches 144which hold the pump motor inoperative until a basket is removed from itsbracket support.

When the unit is to be operated, comestibles are placed in the basketsand one or both of the baskets removed from their bracket support andplaced in the circulating oil in the vessel. Removal of one of thebaskets allows the pump to operate by energizing the pump motor 78 sothat the pump 76 can circulate hot cooking oil through the cookingvessels. At this point, signal light 108 is energized, showing that theunit is in operation. By submerging one of the baskets with comestiblesin it in the vessel, cooking can then take place. After the comestiblesin the basket are cooked and the basket removed and placed back on thehanger support bracket 35, when both baskets are on their supports, thepump hold-out switches 144 stop the pump 76 after a short delay, whichmay be from about 0.5 minute to about 2 minutes, or longer if necessary,to clear the oil of any loose particles by continuing its circulationthrough the filter.

The bottom of each cooking vessel has a drain line 65 in it forcontinuously removing a small quantity of cock ing oil from the bottomof the cooking vessel. It will be appreciated that the quantity ofcooking oil being circulated may be sufiicient to provide turbulence anda sweeping flow by jet stream action directed downwardly and outwardlyso that the hot, fresh, filtered oil passes through and around thecomestibles being cooked and then over the weir and draining of a smallquantity of cooking oil from the bottom of the vessel. After the cookingoperation has been stopped, the cooking oil remaining in the vesselslowly drains from it. The drained oil from the vessels returns to thereservoir to remain there in heated condition ready for use. Thisdraining of the vessels prevents oil from being exposed to theatmosphere and reduces the absorption of oxygen and contaminates in it.Where a semi-continuous operation is used and the oil in the reservoirdrops below a predetermined lower level due to absorption by thecomestibles of the cooking oil, a cut-out switch 132 deenergizes boththe heaters and pump motor and deenergizes the signal light 108 andenergizes the signal light 140 showing that oil needs to be added tothat in the reservoir. The controlling of the desired cookingtemperatures for the cooking operation is accomplished by thermostat 120and overheat thermostat 124, which latter provides for a shut-down ofthe unit when the cooking oil rises above the maximum allowabletemperature. When additional oil is needed it may be added through theoverflow device so as to bring the oil level in the reservoir to theproper level by removing cover 90 and pouring a measured quantity of oilinto the overflow device 34. This adding of a measured quantity of oilbrings the oil in the reservoir to level B which provides suflicient oilfor proper circulation during the cooking operation.

When the cooking oil in the unit, because of long use needs to bechanged, it can be drained from the reservoir through the reservoirdrain 89 at which time the unit can be cleaned and fresh oil placed inthe reservoir.

In an alternate embodiment, the electrical system utilizes the samecomponents and circuiting of FIG. 6 operating in the same way asheretofore described for the prior embodiment, except that the pumphold-out switches 144 are not included so that pump operation is notswitch controlled by the baskets. Thus, with suflicient oil in thesystem as described above, the double pole switch 104 is closed,connecting power to the whole unit. Oil heater switch is then closed,which energizes the automatic circuit to both heaters and pump, thelatter also controllable by manual switch 106 which is then placed at onor closed position. If the oil level is sufficiently high in thereservoir, that is, not significantly below level A, then cut-out switch132 is closed by operation of its actuating float, thus activating thecircuit to thermostats 120, 124 and 142. Preheat thermostat 142,especially advantageous when hard fat is used which solidifies whencold, disconnects through relay 107 the pump only and not the heaters,until the temperature of the fat has risen sufliciently so that it ismolten, when the thermostat then energizes the relay allowing the pumpto circulate the fat. The pump continues to circulate the fat and theheaters continue to heat the fat until the correct temperature isreached, and then control thermostat deenergizes and cuts off the energyto the heater relays 114, shutting ofl the heat, but allowing the pumpto continue operation. If, for any reason, for example, breakage ordamage to a switch, the heaters continue to heat the oil, then theoverheat thermostat 124 acts as an emergency back-up for controlthermostat 120 and shuts the heaters off when the temperature of the oilreaches above the predetermined maximum safe limit.

It will be appreciated that the cut-out switch 132 is set to de-energizethe whole electrical circuit if the level of oil or fat drops to acertain pre-selected level below level A. It will be observed that, whenthe cooking vessels are full, the operating level in the reservoirduring cooking is at its lowest. Thus, when a too low level of oilcauses the pump to shut down, oil starts to drain from the cookingvessels back through lines 65 which raises the oil level in thereservior. This higher level raises the float 134, again closing thecut-out switch 132 which starts the pump, causing it to pump oil out ofthe reservoir and to the cooking vessels. This action drops the oillevel in the reservoir, causing the float, when the oil reaches belowlevel A, to fall opening the cut-out switch 132, which again stops thepump. In this way, when the quantity of oil in the system is too low,cut-out switch 132 is cycled between open and closed condition so thatsignal light blinks on and off to attract attention to the low oilcondition in the system.

Further, when the filter 56 begins to become clogged with overflowedfood particles, cooking oil flows into the cooking vessels faster thanit can drain and flow out through the clogged filter and back to thereservoir. In a manner similar to that just described when system oilquantity is insuflicient, this causes rising and falling of the float asthe oil level fluctuates about level A and the float alternately opensand closes cut-out switch 132, which starts and stops the machine andthe pump, so that signal light 140 flashes on and off to call attentionto the need to clean the filter.

It will be appreciated that the "deep-fat" frying unit of this inventionprovides for an easy and simplified method for keeping it clean sincethe filter 56 can be simply and easily taken out and cleaned. Also, thetray 12, which supports the cooking vessels 32, can be made removable sothat it can be detached from the unit and easily cleaned.

The apparatus of this invention may be used in both large scaleoperations for either semi-continuous or continuous deep-fat frying, andfor small scale intermittent operations such as individual basketdeep-fat" frying. Because of the portability that the smaller unit has,it is particularly adapted for small restaurant kitchens where largequantities of deep-fat fried foods must be processed in a short periodof time during rush periods, and where the quality of the comestiblesmust be such as to give a commercial advantage. The cooked comestibleformed by the process and apparatus of this invention is one that givesa commercial advantage in that it has a lower oil or fat consumption andthus provides a new and novel deep-fat" fried comestible.

It has been found that the method and apparatus of this inventionproduces a deep-fat fried comestible product with an extremely lowcooking medium absorption by weight of product. This is particularlyadvantageous where large quantities of foods are to be fried, such asbreaded chicken, seafood and other food products where cooking mediumabsorption is both important to taste and to crispness. In the field ofFrench fried potatoes, a low cooking medium absorption is at all timesdesirable since this, too, adds to improved taste and crispness of thepotato pieces. Because most of the food products being deep-fat friedtoday in restaurant kitchens are in a frozen or semi-frozen state, it isimportant that good heat transfer be provided when the comestible isbeing cooked so that the cooking time is lowered and the absorption ofthe fat reduced. This is brought about in this invention by thecontinuous flushing of the comestibles with filtered hot cooking mediumin order to produce a cooked product with a minium of absorption.

An example of the low cooking medium absorption of the process of thisinvention is shown in the following example. .Using the fryer unitdescribed above, 200 pounds of frozen comestibles were fried in a periodof five hours. The fryer contanied 50 pounds of heated solid shorteningthat was continuously circulated during frying. The frozen comestiblesconsisted of 140 pounds of chicken pieces pounds of flounder fillets 30pounds of potatoes.

These comestibles in an open mesh basket were immersed in thecirculating fat maintained at a temperature of approximately 330 F.During the cooking, a 60-mesh stainless steel filter screen was filledfour time to a point where it impeded the flow of fat overflowing fromthe cooking vessel. Each time the filter screen was removed and a cleanfilter screen was put in its place without stopping the operation of thefryer.

At the completion of the run, the fat remaining in the fryer was drainedand weighed and it was found that the comestibles had absorbedapproximately 8 percent of the fat. Also, the fat was found to be ciearand bright and free of any rancid odor or taste.

It will be appreciated that the process and apparatus of this inventionprovides for the deep-fat frying of comestibles in a more efficientmanner with the result that an improved product is obtained. This isbecause of the following:

(1) Shorter cooking time-The cooking vessel of this invention is maderelatively small and the distributions are aimed in such a way as tocause a strong flow over and around the comestible contained in thecooking basket. This strong flow prevents fat or oil from congealing onthe comestible, particularly when the comestible is put into the vesselin a frozen condition. The improvement in heat transfer which resultsfrom the flushing action of the fat or oil considerably reduces the timerequired to cook the comestible.

(2) Lower cooking temperatures.The same flushing action which shortensthe cooking time because of better heat transfer also allows a reductionin the temperature of the fat or oil. As frying is carried out at atemperature high enough to damage the fat or oil, a reduction of oiltemperature helps to preserve the quality of the fat or oil. Furtherwith comestibles such as chicken pieces, where the single article has ahigh weight and large cross section, it has been observed that if toohigh a fat or oil temperature is used the outer part of the chicken isburned or over-cooked before the center of the chicken is cooked.

(3) Heavy loading.The same quantity of fat or oil in the cooking vesselinsures rapid replacement of the fat or oil which has given up its heatto the comestible with freshly heated fat or oil. The size of the loadcan thereftfire be made as high as the capacity of the heaters will aow.

(4) Quick heat recovery.The same flushing action of the fat or oil overthe comestible which improves the rate at which the fat or oil gives upits heat to the comestible works in improving the heat transfer as thecooled fat or oil returning from the cooking vessel is made to pass overthe heating units in the reservoir.

(5) Low fat absorption.ln the usual deep fat fryer the cold comestibleto be cooked is immersed into a bath of non-flushing hot fat or oil. Thehot fat or oil immediately surrounding the comestible rapidly loses itsheat and is increased in viscosity and clings to the cold comestible ina layer of partially congealed fat or oil which in addition acts as aninsulation as well as adding to the amount of fat or oi labsorbed by thecomestible.

It will be appreciated that the drain line connecting the bottom of thecooking vessel with the reservoir may be of a diameter sufficient toallow a slow bleeding of cooking medium from the bottom of the vesselduring the cooking operation with the recirculation being sulficient tomaintain the level in the vessel high enough to produce a substantiallyconstant overflow and when the circulation of the cooking medium isdiscontinued to drain the medium from the vessel into the reservoir.Also the drain lines may have a valve means in it to adjust the degreeof drainage and thereby adjust the time required to empty the cookingvessel when the cooking operation is discontinued.

in the deep-fat fryer of this invention, any type of deep-fat cookingmedium may be used, such as solid shortening, oil and the like. Theapparatus is particularly adapted to handle a fat that solidifies oncooling since when the cooking process is not in operation the hot fatdrains into the reservoir before it can solidify where it is maintainedin a liquid state ready for use.

Another advantage of the deep-fat fryer of this invention is that steam,air or other fluids entrained in the cooking medium during cooking, canbe removed from the cooking medium in the reservoir and released toatmosphere through the vent 70 thereby providing an atmospheric headabove the level of the medium in the reservoir and preventing cavitationdue to expanding gases at the pump inlet. This vent also insures thatpressure heads due to high temperature and moisture cannot occur.

It will be apprecaited that additional heating elements can be placed inthe system as for example in and around the reservoir for easy start-upif desired. It will also be appreciated that other means of heating,such as gas heated tubes or coils containing a heating substance, can beused.

Any type of filters may be used for removing the food particles from theoverflowing cooking medium. These may be of the disposable types,reusable types, and made of any suitable material; such as, stainlesssteel, matted fibers or the like. Also, while a positive displacementoil circulating pump of the gear type has been found to produce goodresults, it will be appreciated that other types of pumps may be usedthat are capable of maintaining a continuous circulation of cookingmedium during the cooking operation.

While the invention has been described with particular reference to apreferred embodiment thereof, it will be obvious to those skilled in theart that various changes and modifications may be made without departingfrom the spirit and scope of the invention.

What is claimed is:

1. A method of cooking comestibles by immersion in a hot cooking mediumwhich comprises immersing comestibles in a frying unit having at leastone cooking vessel therein, containing hot cooking medium maintained ata predetermined cooking temperature; continuously flowing the hotcooking medium under pressure into and around the comestible withsutficient force and turbulence to effect high heat transfer so as toprevent cooled, high 13 viscosity cooking medium from clinging to thecomestible so as to inhibit absorption by the comestible of cookingmedium; continuously overflowing the turbulent cooking medium to removeloose particles that have been detached from the comestibles to preventthem from depositing in the bottom of the vessel; filtering the detachedparticles from the cooking medium overflow thereby removing the looseparticles from cooking medium overflow; re-heating said filtered cookingmedium to maintain it at the cooking temperature; continuouslyrecirculating and flowing the heated cooking medium under pressure inquantities sutficient to maintain the volume of cooking medium in thevessel while cooking and provide an overflow that sweeps the looseparticles from the vessel in a turbulent manner; bleeding at smallportion of said cooking medium from the bottom of said vessel into areservoir; and removing the comestibles from the body of cooking mediumwhen cooking is complete, whereby the comestible is cooked rapidly atlower than normal cooking temperatures because of the high rate of heattransfer between the freshly heated turbulent cooking medium and thecomestibles, the fat consumption is reduced because of improved flow ofcooking medium in the vessel and the life of the hot 14 cooking mediumis lengthened because of the removal of loose particles from it.

2. The method of claim 1 in which cooking medium entering the reservoiris deflected upwardly just below the level of the medium in thereservoir.

References Cited UNITED STATES PATENTS NORMAN YUDKOFF, Primary ExaminerM. G. MULLEN, Assistant Examiner US. Cl. X.R.

